svga: add missing fallthrough comments

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5705>
diff --git a/src/gallium/drivers/svga/svga_tgsi_vgpu10.c b/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
index 0c07985..f5a79bd 100644
--- a/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
+++ b/src/gallium/drivers/svga/svga_tgsi_vgpu10.c
@@ -10246,6 +10246,7 @@
                   emit->tes.inner.in_index + 1, TGSI_SWIZZLE_X);
          dst = writemask_dst(&dst, TGSI_WRITEMASK_Y);
          emit_instruction_op1(emit, VGPU10_OPCODE_MOV, &dst, &src);
+         /* fallthrough */
       case PIPE_PRIM_TRIANGLES:
          src = make_src_scalar_reg(TGSI_FILE_INPUT,
                   emit->tes.inner.in_index, TGSI_SWIZZLE_X);
@@ -10277,11 +10278,13 @@
                   emit->tes.outer.in_index + 3, TGSI_SWIZZLE_X);
          dst = writemask_dst(&dst, TGSI_WRITEMASK_W);
          emit_instruction_op1(emit, VGPU10_OPCODE_MOV, &dst, &src);
+         /* fallthrough */
       case PIPE_PRIM_TRIANGLES:
          src = make_src_scalar_reg(TGSI_FILE_INPUT,
                   emit->tes.outer.in_index + 2, TGSI_SWIZZLE_X);
          dst = writemask_dst(&dst, TGSI_WRITEMASK_Z);
          emit_instruction_op1(emit, VGPU10_OPCODE_MOV, &dst, &src);
+         /* fallthrough */
       case PIPE_PRIM_LINES:
          src = make_src_scalar_reg(TGSI_FILE_INPUT,
                   emit->tes.outer.in_index + 1, TGSI_SWIZZLE_X);